It sure sounds like a nice idea. Print a bunch of money and everyone gets rich. We could buy anything we wanted. Ah, if only it were that easy. It turns out printing more money would have a much different outcome than we might like to imagine.

Each planet is a little different on the inside. And what’s inside a planet can shape what’s on the outside, too. That’s what I found out from my friend Steve Reidel, a geologist at Washington State University.

“Well, there’s the rocky planets,” he said. “Then there are the big, gas giants.”

Rocky planets, like Earth, are wrapped in a thick crust. Beneath Earth’s crust is the mantle. The mantle is quite solid, but it actually behaves more like a fluid. It flows and deforms. It’s similar to Silly Putty, but a really strong version of Silly Putty. It’s about 1,800 miles thick. It is also the main source of Earth’s volcanoes.

We’ve got about three pounds of brain in our heads that help us look for answers and solve all kinds of problems. But it isn’t always easy. Sometimes an experiment doesn’t go the way I expect or I get stuck on a particularly tricky science question.

Everything our computers do, they do because we program them to do it. Maybe you want to design a game or an app that’s brand new. To create that game or app, you have to help your computer understand what to do.

You’re right. It can take a really long time for some things to decay.

If we buried an apple peel in the backyard it might only take a few weeks to break down into the soil. But if we buried a plastic water bottle, it would probably still be there hundreds of years from now.

Our world is full of slime makers. Slugs and snails leave behind gooey trails. Bacteria can create layers of slippery slime in water pipes. Even your body makes its own kind of slime. In our joints, we have slime that helps protect our bones.